Grease composition



will;

Patented Aug. 4, 1953 GREASE COMPOSITION Walter H. Peterson, Point Richmond, Calif., as-

signor to Shell Development Company, San Francisco, Calif., a Delaware corporation No Drawing. Application January 27, 1950, Serial No. 140,973

11 Claims. 1

This invention is concerned with improved grease compositions. lates to greases gelled by the presence of inorganic gelling agents such as silica and containing a combination of additive materials for the purpose of improving the water-resistance characteristics of the greases.

Greases are known which contain as their gelling agents certain inorganic materials such as silica aerogels and the like. While these greases exhibit outstanding performance under high temperature conditions, when compared with ordinary soap greases, they also possess inherent sensitivity to destruction by the action of water. Thus, when such greases are used for lubricating purposes when water or water-vapor is present, they tend to separate into two phases, namely an oil phase and a hydrated silica phase with consequent destruction of the grease. A copending patent application by the present inventor, Serial No. 82,905, filed March 22, 1949, now Patent No. 2,573,650 describes the use of certain agents for improving the water-resistance of such greases. The agents described in this copending application are hydroxy-containing organic compounds, as more particularly defined hereinafter. While the use of these compounds improves the water-resistance of the subject greases to a marked extent, there has been room for considerable improvement in this respect.

It is an object of the present invention to provide improved inorganic gel greases. It is another object of the present invention to provide inorganic gel greases having a higher water-resistance than those heretofore produced. It is an additional object of the present invention to provide greases which not only exhibit outstanding resistance to the deleterious action of water, but which also exhibit minimum corrosion characteristics.

Now, in accordance with this invention, it has been found that the resistance of inorganic gel greases to deterioration by water is improved to an unexpected extent by the combined addition thereto of certain hydrophobic surface active hydroxyl-containing organic compounds together with certain succinic or succinamic acids, their anhydrides, esters or amides. Not only do these succinic acid derivatives enhance the waterresistance of the subject greases in an unexplained manner, but they impart improved corrosion characteristics to the greases as well without adversely affecting the grease structure.

The succinic and succinamic acids useful in the present compositions are those bearing alkyl and alkenyl substituents, having from 5 to 36 More particularly, it recarbon atoms and preferably between 10 and 24 carbon atoms.

Alkylated succinic acids are most readily prepared by condensing maleic acid anhydride with individual olefins or mixtures of olefins, particularly monoolefins. The resulting alkenyl succinic acid anhydrides may then be hydrated to liberate the free succinic acids, which may be used as such for blending with the lubricating oil or which may first be hydrogenated to produce the saturated alkyl succinic acids. An illustrative method of preparing these substances is set forth in the Eichwald. patent, U. S. 2,055,456. The term alkyl succinic acids as herein used refers to both the unsaturated as Well as the saturated products obtained when condensing maleic acid anhydride and olefins, hydrating the product to liberate the free acids, and hydrogenating the latter, if desired.

As to the boiling limits of suitable olefins there appear to be no critical limitations affecting the ability to prevent corrosion of the alkyl succinic acids produced therewith. However, it is desirable that the olefins be capable of distillation without substantial decomposition for the purpose of purifying the olefins as well as of separating unreacted olefins from the succinic acids produced therewith. In general, therefore, it is preferred that the normal boiling points of the distillate fractions be above 250 C. but not greatly in excess of 400 C. Most olefins normally boiling below about 400 C. can be distilled readily, if not under normal, then under reduced pressures, Without noticeable decomposition.

Suitable olefins to be used in the condensation reaction mith maleic acid anhydride may be produced by cracking a heavy oil, preferably in the vapor phase, under conditions to yield maximum amounts of the desired high boiling olefins, or else low boiling olefins may be polymerized to yield higher boiling olefins. Of particular usefulness are the normal olefins obtained in the vapor phase cracking of wax at temperatures around 560 0., although branched olefins may be used. The olefins may be of either primary or secondary or tertiary type.

The condensation reaction is carried out by digesting maleic acid anhydride with the desired olefins or olefin fraction at an elevated temp ture, preferably C. to 250 C., and, if desired, in the presence of a mild condensing agent.

The following examples illustrate the preparation of typical preferred alkyl or alkenyl succinic acids.

Three hundred parts of a distillate fraction of vapor phase cracked wax, boiling between 280 C.

greases.

of water corresponding to the 'saponlfication number for one hour at 90 0., whereby the-anhydrides were converted to the free acids. All parts were by Weight.

It will be understood that the subject alkyl and utilized in the form of their anhydrids, free acids, amides, and aliphatic esters. The amides are sometimes regarded as condensation products formed between the succinic acid derivative and an amine. Either monoamides or diamides of the succinic acid derivatives may be employed and, furthermore, the amides may be formed from monoaliphatic amines or from aliphatic polyamines. The diand triamines as well as the hydroxy derivatives thereof have been found to be especially suitable for the formation of effective condensation products with succinic acid for use in the subject compositions.

The condensation products utilized in accordance with the present invention may be prepared by various methods, of which the following are exemplary.

Olefin hydrocarbons containing from to carbon atoms produced by the dehydration of the corresponding alcohols, or by the removal of hydrogen halide from the corresponding hydrocarbon halides, or by the polymerization of lower olefins such as propylene, butylene, isobutylene, the amylenes, and the hexylenes or mixtures thereof, are caused to react with an unsaturated dicarboxylic acid or anhydride under the influence of heat to produce the alkenyl dicarboxylic acid or anhydride. Suitable charge ma terials include maleic anhydride or acid, fumaric acid,- citraconic anhydride or acid, itaconic anhydride or acid, mesaconic acid, glutaconic anhydride or acid, methyl itaconic anhydride or acid, and the like. Alternatively, the alkyl dicarboxylic acid or anhydride may be prepared by hydrogenation of the corresponding C5, to G20 alkenyl dicarboxylic acid or anhydride or by treating a dicarboxylic acid ester with an alkali metal alcoholate in alcohol to replac a hydrogen atom on the alpha carbon atom of the ester with an alkali metal atom, and then reacting this product with an alkyl halide to introduce the alkyl group and eliminate the alkali metal as alkali metal halide. The alkylated dicarboxyic ester may then be reduced to the acid or the anhydride. Another method for producing the C5 to C20 dicarboxylic acid or anhydride comprises treating an unsaturated dicarboxylic acid or anhydride with a hydrogen halide to obtain a halogenated, saturated dicarboxylic acid or anhydride, and then replacing the halogen atom on the alpha carbon atom with an alkyl group by treatment with an alkyl halide and a catalyst or an alkali metal.

The alkyl or alkenyl dicarboxylic acid or anhydride may then be reacted with a monoamine, diamine or polyamine to obtain a condensation Ninety seven parts of a residue were product suitable as an additive for the subject The amines may be employed in molar ratios ranging from 1 to 2, although higher ratios recover the desired acid ester.

.as benzene.

'4 are not detrimental. Molar ratios of 1.3 to 2 have given very good results in the production of the condensation products. The amines which are preferred for the condensation reaction are those containing from 2 to 18 carbon atoms, and may be exemplified by ethylene diamine, diethylene triamine, triethylene tetramine, l-methyl ethylene diamine, l-ethyl ethylene diamine, propylene diamine, butylene diamine, trimethyl trimethylene diamine, tetramethylene diamine, diaminopentane or pentamethylene diamine, dianiinohe'xane, hexamethylene diamine, heptamethylene diamine, diamino-octane, decamethylene diamine, and the higher homologs up to 18 carbon atoms, phenylene diamine, the alkylated phenylene diamines having nuclear substituerits such as methyl, ethyl, propyl, butyl, etc., naphthalene diamine, and the alkylated naphthalene diamines. The condensation reaction may be carried out by simply adding the diamine'or polyamine to the alkyl or alkenyl dicarbox'ylic'acid or anhydride at ordinary temperatiire (60 F. to F.) and then stirring vigorously; As the condensation proceeds, the temperature of the reaction mixture rises to 150 F.-220 F., with the elimination of water produced by the condensation. The condensation products, when cooled to room temperature, range from viscous, yellowish liquids to solids. When the charge materials are themselves solids, the reaction may be initiated by the application of heat suiiicient to render the reactants liquid and capable of being mixed and stirred.

In the preparation of the condensation product of a diamine with an amido carboxylic acid, the latter may first b formed by treating an alkyl or alkenyl dicarboxylic acid or anhydride with ammonia (for example, 28% aqueous ammonia) to form the ammonium salt of the amido carboxylic acid. This product, when acidified with a mineral acid, such as hydrochloric acid, yielded the amido carboxylic acid, which in turn may be condensed with a'diamine by stirring the mixture at ordinary temperature, heat being liberated as the condensation proceeds. The reaction temperature may rise to F.-220 F2, and upon cooling, the condensation products range from extremely viscous, yellow-orange liquids to waxlike solids.

Condensation products also suitable for use in accordance with this invention may be prepared by reacting the acid esters of the alkyl and alkenyl dicarboxylic acids or the acid esters of the alkyl and alkenyl amide carboxylic acids with diamines or polyamines. The acid esters may be produced by' reacting, for example, equimolar quantities of an alcohol with the acid or anhydride. The alcohols may be exemplified by methyl, ethyl, propyl, isopropyl, butyl, amyl, etc. The reactants may be heated to temperatures of the order of 300 F. and maintained at this temperature for 1 to 3 hours, and then distilled to Another method for preparingthe acid esters consists in reacting, for example, equimolar quantities of the acid or anhydride and an alkali metal alcoholateby refluxing the mixture at an elevated temperature for 2 to 8 hours in the presence of a diluent such After refluxing, the alkali may be removed by washing the product with mineral acid, and then'separating the benzene by distillation, leaving thedesired acid ester. To prepare for example, of a diamine and the acid ester are mixed at ordinary temperature and then vigorously stirred. As the condensation progres'ses, the temperature may rise to 120 F.-180 F., and after cooling, there is obtained a condensation product which may range from a viscous oil to a solid. The following is a typical process for the preparation of suitable succinic acid derivatives:

Nonylene, dodecylene, and octadecylene were reacted, respectively, with maleic anhydride by heating at 400 F. in a closed system with no external pressure applied, for a period of 1 to 4 hours. Vacuum distillation of the reaction products yielded the respective nonenyl, dodecenyl, and octadecenyl succinic anhydrides, substantially free of unreacted monoolefins and maleic anhydride. Using equimolar proportions of the monoolefin and the maleic anhydride gave a 40% to 60% yield of the corresponding alkenyl succinic anhydrides, whereas using 4 moles of monoolefin to 1 mole of maleic anhydride gave sub stantially 100% conversion into the corresponding alkenyl succinic anhydride.

The alkenyl succinic anhydrides as above prepared were condensed with ethylene diamine by slowly adding 2 moles of the diamine to the respective anhydrides at room temperature with vigorous stirring. Reaction immediately occurred and the temperature of the reaction mixture rose to 150 F.220 F., with the elimination of byproduct water.

The preferred species of succinic acid derivatives include especially the alkenyl succinic acids wherein the alkenyl groups contain to 24 carbon atoms such as dodecenyl succinic acids, hexadecenyl succinic acids, octadecenyl succinic acids as well as mixtures thereof, such as are obtained by the condensation of maleic acid with mixed olefin hydrocarbons.

As stated hereinbefore, these alkenyl succinic acids may be converted to alkyl succinic acids by hydrogenation, to produce the corresponding preferred series of alkyl succinic acids wherein the alkyl group contains 10 to 24 carbon atoms. Thus, this group includes such typical species as tridecyl succinic acid, pentadecyl succinic acid, heptadecyl succinic acid and homologs thereof.

The preferred classes of succinic anhydrides, succinamic acids and succinamic anhydrides correspond to the above alkyl and alkenyl succinic acids. For example, suitable members of these groups are octadecyl succinic anhydrides, octadecenyl succinamic acid and dodecenyl succinamic anhydride.

The esters are preferably those of aliphatic alcohol having from 1 to 24 carbon atoms such as the methyl esters of octadecenyl succinic acid, the 2-ethylhexyl esters of hexadecyl succinamic acid, and the dodecenyl esters of decenyl suc cinic acid.

The aliphatic hydroxy compound to be used in the subject compositions are those disclosed in the copending patent application referred to hereinbefore. The principal classes useful for protecting the greases described hereinafter are especially hydroxy fatty acids, monohydric alcohol esters of said acids, polyhydric alcohols, esters of glycols and glycerols with hydroxy fatty acids, or esters of any fatty acid with polyhydric alcohol if the latter is only partially esterified, and natural products or modified natural'products containing these types of compounds. It will be understood that other specialized groups of compounds meet the limitations given in the statement with the invention, but that these groups are preferred due to theii availability and eflectiveness.

The text by A. W. Ralston Fatty Acids and Their Derivatives, John Wiley 8: Sons, Inc., 1948, describes the more important types of hydroxy fatty acids and their esters which have been found to be useful in the present invention. The preferred'hydroxy fatty acids useful for increasing the water-resistance of silica greases and the like include especially hydroxy stearic acids, and more particularly, 12-hydroxy stearic acid. Other homologs have been found to be effective as well such as stearic acids having hydroxy substituents in the 9, 10 or 11 positions. Polyhydroxy compounds also are effective, such as 9,10-dihydroxy stearic acid, 3,12-dihydroxy palmitic acid or 9,10,16-trihydroxy palmitic acid. While the saturated acids are preferred, those containing olefinic or acetylenic linkages may be used if available. These include such acids as 12-hydroxy ricinoleic acid, 19-hydroxy nonadecanoic acid and wool wax acids.

The hydroxy fatty acid glycerides which may be used in accordance with this invention are preferably the glycerides of fatty acids containing 8 or more carbon atoms and 1 or more hydroxyl radicals which are separated from the carboxyl group by at least one carbon atom. The:

preferred form of the material, due to availa-- bility and cost, is hydrogenated castor oil. Otherglycerides of hydroxy fatty acids are effective for" the present purpose such as glycerides of the:

hydroxy fatty acids produced by catalytic oxida-- tion of hydrocarbon oils and waxes which have: been extracted and fractionated to a desirable: molecular weight range.

Partial esters of polyhydric alcohols and partial ethers of polyhydric alcohols are effective waterproofing agents for use in the present compositions. The preferred type of esters falling within this class include monoesters of glycerol wherein the ester radical contains at least 8 carbon atoms. A typical member of this class is glycerol monostearate. Ethers of glycerol containing 8 or more carbon atoms in the ether radical are exemplified by the monodecyl ether of glycerol.

The esters of monohydric alcohols with hy-' droxy fatty acids have been found to be effective water-proofing agents. Preferably, the esters are formed from alcohols having from 4 to 16 carbon atoms such as butyl, octyl and dodecyl alcohols together with hydroxy fatty acids such as those described above. A particularly effective member of this series is the butyl ester of 12-hydroxy stearic acid.

Glycols having at least 8 carbon atoms in the molecule also are suitable. Specific members of this class include octane diol, 1,4-dodecane diol, 1,2-decane diol and 1,10-decane diol. It is a preferred practice to apply glycols having widely spaced hydroxyl groups since it has been noted that glycols having hydroxyl groups attached to adjacent carbon atoms soften the grease to a certain extent, but glycols having widely spaced hydroxyl groups do not affect the grease in this manner. The lower polymers of alkylene glycols such as polyethylene glycol and polymethylene glycol are suitable water-proofing agents. The molecular weight ofthese polymers should be at least about 200 and preferably not more than about 800. Polyalkylene glycols having one of the end hydroxyl groups in the form of an ether or ester may be used as well. A typical member ofthis class is the monobutyl ether of tetraethylene glycol...

Higher molecular weight monohydric alcohols may be used such as octyl, decyl, dodecyl, stearyl and similar aliphatic monohydric alcohols. As was noted above, the corresponding; mercapto compounds are effective for. the present purpose and include especially higher molecular weight mercaptans such. as dodecyl mercaptan.

The amounts of hydroxy. compound and ofsuc cinic acid derivatives shouldvary from about 10 to 7.0% by weight of the gel and preferably is present in an amount between. '20 to 50%. Based on the total grease the amounts of the additives are between 0.5 to,10%, preferably 1 to 5%. The effective amount of. hydroxy compound required for improvingthe water-resistance. of theg-reases described will vary with a number of factors; these include the molecular weight of the compound, the number of. effective active groups such as hydroxyls, the amount of'silica' or other gel to be protected, and the surface area of' said gel. The latter will depend upon the preparation of the gel and its subsequent grinding or reduction in particle size. The amount of silica or other gel will depend upon the grease consistency required. Ordinarily stated in terms of equivalence of effectivehydroxyls it has-been ascertained that from about .03 to about .10 equivalent of hydroxyls per 100' grams-of silica gel'provide excellent water protection for-thegreases; Preferably, the hydroxyl equivalent is between .05 to .08-per 100 grams ofsilica. The equivalent value is determined by dividing the molecular weight of' a givenhydroxy compound-by the number of-effective: hydroxyl groups in the molecule.

The oil component of the subject grease compositions may be described broadly as anoleagi'nous vehicle whichincludes the conventional mineral'lubri'cating oils, the synthetic lubricating oils prepared by. cracking and polymerizing products ofqthe Fjischer 'liropsch processand-the like; or a syntheticoleaginousmompound within the lubrieating oilviscosity range. The-synthetic oleaginous compounds are those which possess lubricating characteristicsorrto which such characteristics.may be-imparted'and may be substituted in whole or inapart. for the conventional mineraldubricating oils.- Examples of these compounds are the aliphatic--.dicarboxylic acid esters such as the alkylestersof sebacic acid, the highmolecular weight aliphatic: ethers as-n-hex-yl ether and the aromatic'acid-zesterssuch as the alkyl estersof benzoic: or phtha lic acids. Other suitable synthetic lubricant'sdnclude organic phosphates such as tricresyl phosphate, tributyl. phosphate and mixed phosphates such as butyl dibenzylphosphate; A. special class of lubricants comprise the silicon oils which ordinarily require modification by the presenceof a Secondary-lubricant orthe useof lubricity imparting additives such as -extreme pressure additives.

The agents which may be employed for the formation of: greasesin the oily fluids defined above include inorganic gels such as silicagel and other gels-of'inorganic oxides, hydroxides, sulfides and the like It has been found to-be substantially essential that thegels beusedinanonshrunken state such-as may be obtained in the so-calledaerogelform'ation. Other means will be described' herelnafter whereby gels suitablefor useinthe-formation of greasesmay be prepared by other processesthan aerogel formation. Typical' aerogel greasesare described in a patent to Kistler; US S.-.2,260,6'25; Other'aerogelswhich are-useful include magnesia; alumina, calcium oxide and the like. Hollow spheroidal gels, such 8. as those described by E. L. Largent in U. S. Patent 2,449,253, may be used in grease compositions.

One disadvantage which has been noted with respect to aerogels is their high bulk density. In accordance with one phase of the present invention, a means has been found for reducing the bulk density of aerogels and at the same time maintaining their ability to form greases with oleaginous components. This process comprises wetting the aerogel prepared after the manner described by Kistler with organic solvents such as acetone and isopentane. Other solvents comprise alcohols such as butyl alcohol, aldehydes such as acetaldehyde and similar low-boiling liquids having no solvent action on the aerogel and no chemical reaction therewith. The process comprises wetting the aer'ogel with a sumcient amount of the solvent such as acetone at room temperature and removing the solvent by warming why the use of vacuum. 'I'he'untre'ated aerogel'has been found to be difl'icult to handle due to its high bulk density, while the treated aerogel appears to be in a more'readily usable form resembling porous brittle aggregate lumps which are easily crushed to a powder.

The classes of polyvalent metal oxides and'hydroxides forming gels are well known and do not require extensive discussion. The oxides and hydroxides of' silicon, aluminum, chromium, copper, iron, manganese, titanium, nickel, calcium, germanium, molybdenum, thorium, tin and lead, and the like.

One of the means for-preparing greases from inorganic gels without resorting-to aerogel formation comprises dispersing an alcoholate or ester of the same group of metallic substances recited above in. the lubricating medium and subse-' quently hydrolyzing to form the gel in situ, finally. removing alcohol: or other non-metallic productsof the hydrolysis. This method inherently entails the advantage of avoiding: aerogel formation and at the same time ensures the preparation of smooth, evenly dispersed greases having uniform structure.

A third method for the preparation of inorganic greases comprises formation of the hydrogel by'well known processes commencingwvith an inorganic salt such as aluminum sulfate; By treatment of the salt dissolved in water withan agent such as ammonia, the hydrogel may be prepared and subsequently dehydrated by azeotropic distillation in the presence of a lowerboiling alcohol such as ethanol. The alcohol suspensionofthe gel is then transferred to the lubricating oil medium afterwhich alcohol is removed-by distillatiompreferably in vacuum. Upon removal of the alcohol and subsequent milling, a grease structure results wherein the inorganic gel is uniformly dispersed throughout the lubricating medium.

Effective-amounts of' gelling ingredients ordinarily are from about 1 to about 20% by weight of the oleaginous base. Preferably, the amount of gellingagent is from about 2 to 10% by weight of the oleaginous base.

The greases may be. prepared as described above, either by separate preparation of the nonshrunken gel or by formation of the gel in the presence of the oil. The addition of waterproofing hydroxy compounds such as those described hereinbefore is preferably carried out subsequent to grease formation. It has been found that the degree of water-proofing for a given amountlof the hydroxycompound issubstantially. greater if addition'is effected at this stage rather than prior to grease formation. However, veffective water-proofing has been found to take place by initially dissolving the hydroxy compound in the oily medium and subsequently dispersing or forming the gel therein.

An additional type of inorganic gel grease which may be improved according to the present invention comprises greases gelled by the presence of organophilic clays and the like. The clays to be used in the present instance comprise those which have been treated with organic cationic surface active agents such as quaternary ammonium salts so as to destroy their inherent hydrophilic nature and to impart organophilic characteristics thereto. The essential preparation of greases of this character comprise dispersing a swelling type of bentonite in water to form a hydrosol and adding 10 to 50% by weight of an ammonium salt such as dicetyl methyl am-v monium chloride which causes the formation of a hydrogel wherein either absorption or ion exchange reaction has occurred so that a closely bonded composition of the bentonite andammonium salt has resulted. The ammonium compound treated clay may then be incorporated directly with oil by milling together with simultaneous or subsequent heating for the removal of water. This method of direct transfer from a hydrogel into oil with the formationof grease omitting any intermediate organogel formation or drying step is one which has been found to be highly desirable from an economic standpoint. While the addition of substituted succinic acids to the resulting greases has been found to result in improved water-resistance thereof, it is desirable to add as well one of the hydroxy-containing, surface active organic compounds as detailed above. Clays which are useful for the present purpose include especially montmorillonite such as the Wyoming bentonites r hectorite. While the swelling type of clays are those most highly desired, it is possible to prepare greases from the non-swelling type of clays, although larger amounts will be necessary to prepare a grease of a given penetration.

Summarizing the compositions described hereinabove, the preferred greases will contain the following ranges of proportions of their ingredients:

Per cent by weight of composition Lubricating oil 60-98 Inorganic gelling agent 1-20 Hydroxy additive -10 Succinic acid derivative -10 It has been found that while the above ran of ingredients are satisfactory in most instances, a clearer description may be made by reference of the ratio of hydroxy additive and succinic acid derivative based on the inorganic gel rather than upon the total. grease composition. Hence, preferred compositions are those containing up to 20% of the inorganic gel based-on the total grease and also containing 1 to 50% by weightof the inorganic gel of both the hydroxy-containing surface active agent and of the succinic acid derivative.

The following examples illustrate the advantages to be gained from the present compositions:

Example I A mineral lubricating oil was milled with 5% by weight of a silica alcogel prepared by displacement of water from a silica hydrogel. During the milling operation, 2.4% of the triglyceride of 12-hydroxy stearic acid were added to the mixture and the ingredients were milled to form a grease. A similar grease was prepared which contained none of the glyceride additive. Following the milling operation, the greases were heated for a period of about one hour at a temperature of about 150 to 210 C. The grease containing only silica and lubricating oil disintegrated rapidly in the presence of boiling water. A sample of the grease prepared with silica and lubricating oil was modified by the addition of 1% by weight of the grease of octadecenyl succinic acids. This grease likewise disintegrated rapidly in the presence of boiling water. The silica grease containing the glyceride additive exhibited satisfactory resistance to boiling water. A fourth grease which contained the same amounts of both the glyceride additive and of octadecenyl succinic acids also showed satisfactory stability in the presence of boiling water. The four greases described above were then subjected to a roll stability test under the following conditions: '74 g. of the grease and 14 g. of water were rolled in a Shell Roll Tester (reference) and periodically tested until the grease reached a micro penetration of 230. It was found that the silica grease containing no additives failed almost at once. The silica grease containing only octadecenyl succinic acids failed in about one hour. The grease containing the glyceride additive failed in 12 hours, while the grease containing both additives lasted for 52 hours before failure.

Example II Silica hydrogel was treated with aluminum sulfate to form a silica alumina hydrogel (composition). A 5% grease was prepared from the M present silica alumina hydrogel by dehydrating the hydrogel with an ethyl alcohol, incorporating the organoge1 in mineral oil and evaporating off the alcohol. Three greases were prepared: Grease A contained no additives. Grease B contained 2% by weight of the triglyceride of 12- hydroxy stearic acid. Grease C was the same as grease B, but in addition contained 1 by weight of octadecenyl succinic acids. Each of the three greases contained 5% by weight of the silica alumina gel. For comparison two of the greases from Example I also were tested. Sample D was the-grease from Example .1 containing the glyceride of 12-hydroxy stearic acid and sample'E was the grease from Example I containing both the glyceride and octadecenyl succinic acid. The greases described herewith were tested by smearing a layer of the grease on a steel strip which was then immersed in water contained in a test tube. The tube was placed in a steam bath and observed periodically for oil separation. The

figures given in the table below represent'the heating time in hours necessary to cause oil separation.

Hours under Silica alumina Silica alumine+glyceride 16.

Silica alumina+glyceride+succinlc acid derivative greater than 31. Silica+glyceride l. Silica-hglyceride-l-succinic acid derlvative 5.

Example IH When greases are prepared by dispersing 5 parts by weight of the listed gelling agents, 1 part by weight of the succinic acid derivative and 2 parts by weight of the surface active agent and 92 parts by weight of the mineral lubricating oil, the compositions which result are found to have excellent resistance to theaction of hot Water. If the surface active agent is omitted from any of the compositions, the grease which is formed from the remaining three components is found to be extremely sensitive to the action of cold water and to disintegrate immediately when contacted with hot water. Greases containing the gelling agents, mineral oil and surface active agent while showing moderate resistance to the action of cold water are quickly disintegrated in A grease was prepared containing 6% by weight of silica alcogel, 1% by weight of glycerol monostearate and 1% by weight of octadecenyl succinic acid. A similar grease was prepared omitting octadecenyl succinic acid. The first grease was found to have a hot water stability three times as great as that of the second grease.

I claim as my invention:

1. A grease composition comprising a mineral lubricating oil, 2-10% by weight of silica gel having a structure substantially that as originally formed, 1-5% by weight of 1,2-decamethylene glycol, and 1-5% by weight of hexadecenyl succinamic acid.

2. A grease composition comprising a mineral lubricating oil, 210% by weight of silica gel having a structure substantially that as originally formed, 1-5% by weight of a glyceride of 12- hydroxy stearic acid, and 15% by weight of octadecenyl succinic acid.

3. A grease composition comprising a mineral lubricating oil, 1-20% by weight of an inorganic oxide gel having a structure substantially that as originally formed, 05-10% by weight of a hydrophobic alkylene glycol having at least 8 carbon atoms and 05-10% by weight of a 05-35 alkenyl succinamic acid.

4. A grease composition comprising a mineral lubricating oil, 1-20% by weight of a silica gel having a structure substantially that as originally formed, 05-10% by weight of a glyceride of 12- hydroxy stearic acid, and 05-10% by weight of an octadecenyl succinic acid.

5. A grease composition comprising a mineral lubricating oil, 1-20% by weight of an inorganic oxide gel having a structure substantially that as originally formed, 05-10% by weight of an ester of a hydroxy fatty acid having at least 8 carbon atoms, and 05-10% by weight of an alkenyl succinic acid having at least one alkenyl group of to 24 carbon atoms.

6. A grease composition comprising a mineral lubricating oil, 1-20% by weight of an inorganic oxide gel having a structure substantially that as originally formed, 05-10% by weight of a hydroxy fatty acid having at least 8 carbon atoms, and 05-10% by weight of an alkyl succinic acid 12 having at least one alkyl substituent of 10 to 24 carbon atoms.

7. A grease composition comprising a lubricating oil, 1-20% by weight of an originally hydrophilic inorganic gelling agent capable of forming a grease structure in said oil, 05-10% by weight of a hydroxy-containing hydrophobic surface-active agent of the groups consisting of hydroxy fatty acids, aliphatic alcohols having at least 8 carbon atoms per molecule, aliphatic esters of said acids and of said alcohols wherein each ester molecule contains at least 1 hydroxyl group, and mixtures of the same and 05-10% by weight of an alkyl succinic acid bearing at least one hydrocarbon group having from 5 to 36 carbon atoms.

8. A grease composition comprising a lubricating oil, 1-20% by weight of an originally hydrophilic inorganic gelling agent capable of forming a grease structure in said oil, 05-10% by weight of a hydroxy-containing hydrophobic surface-active agent of the groups consisting of hydroxy fatty acids, aliphatic alcohols having at least 8 carbon atoms per molecule, aliphatic esters of said acids and of said alcohols wherein each ester molecule contains at least 1 hydroxyl group, and mixtures of the same and 05-10% by weight of an alkenyl succinic acid bearing at least one hydrocarbon group having from 5 to 36 carbon atoms.

9. A grease composition comprising a lubricating oil, 1-20% by weight of an originally hydrophilic inorganic gelling agent capable of forming a grease structure in said oil, 05-10% by weight of a hydroxy-containing hydrophobic surface-active compound of the groups consisting of hydroxy fatty acids, aliphatic alcohols having at least 8 carbon atoms per molecule, aliphatic esters of said acids and of said alcohols wherein each ester molecule contains at least 1 hydroxyl group, and mixtures of the same and 05-10% by weight of a substance of the group consisting of alkyl and alkenyl aliphatic dicarboxylic acids wherein the two carboxyl groups are separated by not more than 3 carbon atoms, and the anhydrides, half-amides and aliphatic esters of said acids, said substances hearing at least one hydrocarbon group having from 5 to 36 carbon atoms.

10. A grease composition comprising a mineral lubricating oil, 2-10% by weight of an inorganic oxide gel capable of forming a grease structure in said oil, 1-10% by weight of 12-hydroxystearic acid and 1-5% by weight of an alkenyl succinic acid having an alkenyl group of 10 to 24 carbon atoms.

11. A grease composition comprising a mineral lubricating oil, 2-10% by weight of an inorganic oxide gel capable of forming a grease structure in said oil, 1-10% by Weight of a hydrophobic hydroxy fatty acid and 15% by weight of an alkenyl succinic acid having an alkenyl group of 10 to 24 carbon atoms.

WALTER H. PETERSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,124,628 Moser July 26, 1938 2,133,734 Moser Oct. 18, 1938 2,260,625 Kistler Oct. 28, 1941 2,445,936 Butcosk July 27, 1948 2,491,441 Butcosk et a1 Dec. 13, 1949 

9. A GREASE COMPOSITION COMPRISING A LUBRICATING OIL, 1-20% BY WEIGHT OF AN ORIGINALLY HYDROPHILIC INORGANIC GELLING AGENT CAPABLE OF FORM-D ING A GREASE STRUCTURE IN SAID OIL, 0.5-10% BY WEIGHT OF A HYDROXY-CONTAINING HYDROPHOBIC SURFACE-ACTIVE COMPOUND OF THE GROUPS CONSISTING OF HYDROXY FATTY ACIDS, ALIPHATIC ALCOHOLS HAVING AT LEAST 8 CARBON ATOMS PER MOLECULE, ALIPHATIC ESTERS OF SAID ACIDS AND OF SAID ALCOHOLS WHEREIN EACH ESTER MOLECULE CONTAINS AT LEAST 1 HYDROXYL GROUP, AND MIXTURES OF THE SAME AND 0.5-10% BY WEIGHT OF A SUBSTANCE OF THE GROUP CONSISTING OF ALKYL AND ALKENYL ALIPHATIC DICARBOXYLIC ACIDS WHEREIN THE TWO CARBOXYL GROUPS ARE SEPARATED BY NOT MORE THAN 3 CARBON ATOMS, AND THE ANHYDRIDES, HALF-AMIDES AND ALIPHATIC ESTERS OF SAID ACIDS, SAID SUBSTANCES BEARING AT LEAST ONE HYDROCARBON GROUP HAVING FROM 5 TO 36 CARBON ATOMS. 